Question

(13-5+6)-(21+2-18)+(7-5)-(8-2+1)

Answer 1

(13-5+6)= 2
(21+2-18)=5
(7-5)=2
(8-2+1)=7

(2)-(5)+(2)+(7)= | 6 |

Answer 2

(13-5+6)-(21+2-18)+(7-5)-(8-2+1)
(8+6)-(21-16)+2-(6+1)
14-5+2-7
9-5=
4